usb: ehci-mx6: Split usb_power_config()

usb: ehci-mx6: Split usb_power_config()

Split usb_power_config() per SoC and pass in USB PHY, USBNC and ANATOP
addresses instead of ad-hoc sequence numbers. This is only applicable
on legacy systems which do not implement proper PHY support. Once PHY
support is available, parts of this can be removed altogether and moved
to the PHY driver, similar to Linux phy-mxs-usb.c .

Fixes: 4de51cc25b5 ("usb: ehci-mx6: Drop assignment of sequence number")
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Fabio Estevam <festevam@gmail.com>
Cc: Peng Fan <peng.fan@nxp.com>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Ye Li <ye.li@nxp.com>
Cc: uboot-imx <uboot-imx@nxp.com>